github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-28 09:04:39 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

LoongArch: Add crash dump support for kexec_file

Browse Source 
Enabling crash dump (kdump) includes:
- Prepare contents of ELF header of a core dump file, /proc/vmcore,
  using crash_prepare_elf64_headers().
- Add "mem=size@start" parameter to the command line and pass it to the
  capture kernel.  Limit the runtime memory area of the captured kernel
  to avoid disrupting the production kernel's runtime state.
- Add "elfcorehdr=size@start" parameter to the cmdline.

The basic usage for kdump (add the cmdline parameter crashkernel=512M
to grub.cfg for production kernel):

1) Load capture kernel image (vmlinux.efi or vmlinux can both be used):
 # kexec -s -p vmlinuz.efi --initrd=initrd.img --reuse-cmdline

2) Do something to crash, like:
 # echo c > /proc/sysrq-trigger

Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Youling Tang 2025-10-02 22:39:08 +08:00 committed by Huacai Chen
parent fc9c112f80
commit 1bcca8620a
1 changed files with 115 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

115
arch/loongarch/kernel/machine_kexec_file.c
View File

@ -55,6 +55,81 @@ static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmpl
*cmdline_tmplen += initrd_strlen;
}
#ifdef CONFIG_CRASH_DUMP
static int prepare_elf_headers(void **addr, unsigned long *sz)
{
int ret, nr_ranges;
uint64_t i;
phys_addr_t start, end;
struct crash_mem *cmem;
nr_ranges = 2; /* for exclusion of crashkernel region */
for_each_mem_range(i, &start, &end)
nr_ranges++;
cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
if (!cmem)
return -ENOMEM;
cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
for_each_mem_range(i, &start, &end) {
cmem->ranges[cmem->nr_ranges].start = start;
cmem->ranges[cmem->nr_ranges].end = end - 1;
cmem->nr_ranges++;
}
/* Exclude crashkernel region */
ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
if (ret < 0)
goto out;
if (crashk_low_res.end) {
ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
if (ret < 0)
goto out;
}
ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
out:
kfree(cmem);
return ret;
}
/*
* Add the "mem=size@start" command line parameter to command line, indicating the
* memory region the new kernel can use to boot into.
*/
static void cmdline_add_mem(unsigned long *cmdline_tmplen, char *modified_cmdline)
{
int mem_strlen = 0;
mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
crashk_res.end - crashk_res.start + 1, crashk_res.start);
*cmdline_tmplen += mem_strlen;
if (crashk_low_res.end) {
mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
crashk_low_res.end - crashk_low_res.start + 1, crashk_low_res.start);
*cmdline_tmplen += mem_strlen;
}
}
/* Add the "elfcorehdr=size@start" command line parameter to command line. */
static void cmdline_add_elfcorehdr(struct kimage *image, unsigned long *cmdline_tmplen,
char *modified_cmdline, unsigned long elfcorehdr_sz)
{
int elfcorehdr_strlen = 0;
elfcorehdr_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "elfcorehdr=0x%lx@0x%lx ",
elfcorehdr_sz, image->elf_load_addr);
*cmdline_tmplen += elfcorehdr_strlen;
}
#endif
/*
* Try to add the initrd to the image. If it is not possible to find valid
* locations, this function will undo changes to the image and return non zero.
@ -82,6 +157,46 @@ int load_other_segments(struct kimage *image,
/* Ensure it's null terminated */
modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
#ifdef CONFIG_CRASH_DUMP
/* Load elf core header */
if (image->type == KEXEC_TYPE_CRASH) {
void *headers;
unsigned long headers_sz;
ret = prepare_elf_headers(&headers, &headers_sz);
if (ret < 0) {
pr_err("Preparing elf core header failed\n");
goto out_err;
}
kbuf.buffer = headers;
kbuf.bufsz = headers_sz;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf.memsz = headers_sz;
kbuf.buf_align = SZ_64K; /* largest supported page size */
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = true;
ret = kexec_add_buffer(&kbuf);
if (ret < 0) {
vfree(headers);
goto out_err;
}
image->elf_headers = headers;
image->elf_load_addr = kbuf.mem;
image->elf_headers_sz = headers_sz;
kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
/* Add the mem=size@start parameter to the command line */
cmdline_add_mem(&cmdline_tmplen, modified_cmdline);
/* Add the elfcorehdr=size@start parameter to the command line */
cmdline_add_elfcorehdr(image, &cmdline_tmplen, modified_cmdline, headers_sz);
}
#endif
/* Load initrd */
if (initrd) {
kbuf.buffer = initrd;